The stereoscopic visualization of CAT scan data would be a great step forward in obtaining a better concept of treatment volumes for radiation therapy planning. At present, only one or two CAT slices are used for treatment planning, and they are usually taken through the central ray. In several anatomical situations, it is important to obtain off-axis data, with respect to the relative position of sensitive organs. The CAT scan data is too voluminous to be easily interpreted by the observer, and still presents a discontinuous picture. Also, a three dimensional view of the isodose curves could be obtained, factoring in such elements as fall-off at the edges, etc. We propose here to study the feasibility of developing such a digital soft-copy-display viewing capability. This project, if successful, would enhance intelligence of the target volume, and also fulfill one of the perennial aims of radiation therapy: how to maximize the dose to the tumor while sparing adjacent critical organs.